Non-Linear Stress Analysis of Complex Umbilical Cross-Sections

2002 ◽  
Author(s):  
Svein Sævik ◽  
Knut I. Ekeberg
Keyword(s):  
Cross Section ◽  
Axial Force ◽  
Plastic Material ◽  
Axial Strain ◽  
Development Program ◽  
Full Scale ◽  
Small Scale ◽  
Applied Theory ◽  
Element Formulation ◽  
Material Models

Nexans Norway is, together with Marintek, currently developing a software for detailed analysis of complex umbilical cross-section designs. The software development project combines numerical methods with small-scale testing of involved materials, as well as full-scale testing of a wide variety of umbilical designs, essential for calibration and verification purposes. Each umbilical design is modelled and comparisons are made with respect to global behaviour in terms of: • Axial strain versus axial force; • Axial strain versus torsion; • Torsion versus torsion moment for various axial force levels; • Moment versus curvature for different tension levels. The applied theory is based on curved beam and curved axisymmetric thin shell theories. The problem is formulated in terms of finite elements applying the Principle of Virtual Displacements. Each body of the cross-section interacts with the other bodies by contact elements which are formulated by a penalty formulation. The contact elements operate in the local surface coordinate system and include eccentricity, surface stiffness and friction effects. The software is designed to include the following functionality: • Arbitrary geometry modelling including helical elements wound into arbitrary order; • The helical elements may include both tubes and filled bodies; • Elastic, hyper-elastic, and elastic-plastic material models; • Initial strain; • Contact elements, including friction; • Tension, torsion, internal pressure, external pressure, bending and external contact loading (caterpillars, tensioners, etc.). The paper focuses on the motivation behind the development program including a description of the different activities. The theory is described in terms of kinematics, material models and finite element formulation. A test example is further presented comparing predicted behaviour with respect to full-scale test results.

Advances in Design and Installation Analysis of Pipelines in Congested Areas With Rough Seabed Topography

2004 ◽  
Author(s):  
Svein Sævik ◽  
Egil Giertsen ◽  
Vidar Berntsen
Keyword(s):  
Plastic Material ◽  
Structural Response ◽  
Element Formulation ◽  
Material Models ◽  
Curved Pipe ◽  
Seabed Topography ◽  
Departure Angle ◽  
Elastic Plastic Material ◽  
Linear Geometry ◽  
Principle Of Virtual Displacements

The present paper addresses a method for simulation of deepwater pipeline installation in offshore fields with rough seabed topography focusing on verification of installation feasibility. The method enables 3D pipe lay analysis to be carried out as a set of subsequent static analyses where the vessel is moved forward automatically considering the restraints from lay vessel departure angle and arbitrarily curved pipe routing. The analysis includes the effect of seabed topography from survey data and variable seabed conditions. The numerical algorithm is seamlessly integrated with 3D graphics for visualization of both the seabed terrain and the structural response of the pipe as the vessel is moving forward. The numerical method is based on finite elements that are formulated by applying the Principle of Virtual Displacements. Large deformations, non-linear geometry and contact effects are taken into account. In addition, elastic and elastic-plastic material models are allowed for, both for the pipe and the seabed contact elements. The paper focuses on the procedure including a brief theory description addressing the specialities needed in this case with respect to kinematics, material models and finite element formulation. The developed procedure is then demonstrated both by analytical and real pipeline installation test examples.

Full Scale Application of Thermal Ageing in Line Pipe Material Selection for Deepwater Pipelines

2014 ◽  
Author(s):  
Niels Kerstens ◽  
Ping Liu ◽  
Duane DeGeer
Keyword(s):  
Wall Thickness ◽  
Development Program ◽  
Thermal Ageing ◽  
Full Scale ◽  
Small Scale ◽  
Pipe Material ◽  
The South ◽  
Line Pipe ◽  
Material Development ◽  
South Stream

Comprising 4 pipelines over 900 km in length, with 32-in diameter and traversing water depths over 2200 m, the South Stream project requires a step-out in technology application. Following several years of preparation, the project is now approaching its implementation. In order to document the reliability of the collapse resistance for South Stream, an extensive material development program was initiated and executed, including small scale, medium scale, and full scale testing on over one hundred purposely manufactured pipe joints by world’s 5 leading mills. Testing performed included plate tests, full scale collapse tests on various combinations of plate sources, steel grades, and thermal ageing condition, pressure-bend tests, and reverse bending tests. A large number of medium and small scale tests were performed to allow the development of a suitably reliable statistical database for the probabilistic wall thickness design. In addition, programs were developed and executed for weldability tests, performing over one hundred trial welds, and for H2S resistance tests. This material development program was built on INTECSEA’s extensive experience with deep water large diameter pipelines (i.e. Oman-India, Blue Stream, Medgaz, Mardi Gras, IGI, etc.). Due to its extent and rigorous approach the South Stream material development program was able to conclusively prove the feasibility of the selected technological approach at an industrial scale. This paper provides an overview of the key design issues that were successfully addressed and the major technological advances that have been implemented as part of the linepipe material development process for deepwater pipelines in an H2S containing environment. The practical significance of this program is to optimize the wall thickness to a level that is manufacturable by the industry and hence enables the South Stream Project to proceed with its unprecedented depth and diameter combination.

Systematic Integration of Finite Element Methods Into Multibody Dynamics Considering Hyperelasticity and Plasticity

2014 ◽  
Vol 9 (4) ◽  
Author(s):  
Graham Sanborn ◽  
Juhwan Choi ◽  
Joon Shik Yoon ◽  
Sungsoo Rhim ◽  
Jin Hwan Choi
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Shell Element ◽  
Rigid Bodies ◽  
Rigid Body Dynamics ◽  
Nonlinear Material ◽  
Element Formulation ◽  
Material Models ◽  
Flexible Bodies ◽  
Body Dynamics

This study proposes a systematic extension of a multiflexible-body dynamics (MFBD) formulation that is based on a recursive formulation for rigid body dynamics. It is extended to include nonlinear plastic and hyperelastic material models for the flexible bodies. The flexible bodies in the existing MFBD formulation use a finite element formulation based on corotational elements. The rigid bodies and flexible bodies are coupled using the method of Lagrange multipliers. The extensions to add plasticity and hyperelasticity are outlined. A solid, brick-type element and a shell element are adapted from the literature for use with the plastic material, and a constant volume constraint is introduced to enforce the approximation of incompressibility with the hyperelastic materials. A brief overview of the MFBD formulation and the details required to extend the formulation to incorporate these nonlinear material models are presented. Numerical examples are presented to demonstrate the feasibility of the model.

Planning Replicable Small Flow Wastewater Treatment Facilities in Developing Nations

1993 ◽  
Vol 28 (10) ◽  
pp. 1-8 ◽  
Author(s):  
A. Gaber ◽  
M. Antill ◽  
W. Kimball ◽  
R. Abdel Wahab
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Local Development ◽  
Treatment Plant ◽  
Development Program ◽  
The United States ◽  
Appropriate Technology ◽  
Funding Agency ◽  
Small Scale ◽  
Technology Choice

The implementation of urban village wastewater treatment plants in developing countries has historically been primarily a function of appropriate technology choice and deciding which of the many needy communities should receive the available funding and priority attention. Usually this process is driven by an outside funding agency who views the planning, design, and construction steps as relatively insignificant milestones in the overall effort required to quickly better a community's sanitary drainage problems. With the exception of very small scale type sanitation projects which have relatively simple replication steps, the development emphasis tends to be on the final treatment plant product with little or no attention specifically focused on community participation and institutionalizing national and local policies and procedures needed for future locally sponsored facilities replication. In contrast to this, the Government of Egypt (GOE) enacted a fresh approach through a Local Development Program with the United States AID program. An overview is presented of the guiding principals of the program which produced the first 24 working wastewater systems including gravity sewers, sewage pumping stations and wastewater treatment plants which were designed and constructed by local entities in Egypt. The wastewater projects cover five different treatment technologies implemented in both delta and desert regions.

scholarly journals Upscaling THM modeling from small-scale to full-scale in-situ experiments in the Callovo-Oxfordian claystone

2021 ◽  
Vol 144 ◽  
pp. 104582
Author(s):  
D.M. Seyedi ◽  
C. Plúa ◽  
M. Vitel ◽  
G. Armand ◽  
J. Rutqvist ◽  
...  
Keyword(s):  
Full Scale ◽  
Small Scale ◽  
In Situ Experiments

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

Full Scale Fatigue Experiment on Submarine Pipelines

2014 ◽  
Vol 633-634 ◽  
pp. 659-664 ◽  
Author(s):  
Zong Tao Fang ◽  
De Yu Tang ◽  
Yan Hua Hu ◽  
Hu Li Niu
Keyword(s):  
Welded Joints ◽  
Fatigue Property ◽  
Full Scale ◽  
Small Scale ◽  
Test Machine ◽  
Butt Joints ◽  
Weld Toe ◽  
Small Test ◽  
Weld Root ◽  
Fatigue Experiment

This paper focus on fatigue problem of submarine pipelines, four points bending full scale fatigue experiment were conducted on X65 pipelines butt joints specimens, utilizing pipeline full scale fatigue test machine developed by CNPC. Meanwhile contrast test was also carried out on small specimens. The results show that the fatigue strength of full scale welded joints is lower than the small scale joints. Owing to having no regard for the influence of residual stress and size effect, the small test would provide dangerous results. The fatigue property of full scale welded joints only meets the requirement of DNV C203 W3 curve, and meets the needs of DNV C203 F3 curve basically while not meet BS 7608 F2 curve’s requirements which relatively demand higher. Weld toe and geometric discontinuous near weld root is the weak point for the whole welded joints.

Coupled Thermo-Hydro-Geochemical Models of Engineered Barrier Systems: The Febex Project

2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  
Keyword(s):  
Large Scale ◽  
Reference Model ◽  
Numerical Models ◽  
Full Scale ◽  
Small Scale ◽  
Model Parameters ◽  
In Situ Test ◽  
Wide Range ◽  
Engineered Barrier

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.

Preliminary Evaluation of the 24 Ft. Diameter Fan Performance In the MinWaterCSP Large Cooling Systems Test Facility

2021 ◽  
Author(s):  
S. J. van der Spuy ◽  
D. N. J. Els ◽  
L. Tieghi ◽  
G. Delibra ◽  
A. Corsini ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Static Pressure ◽  
Cooling System ◽  
Pressure Rise ◽  
Full Scale ◽  
Test Facility ◽  
Small Scale ◽  
Preliminary Evaluation ◽  
Cfd Analysis ◽  
Setting Angle

Abstract The MinWaterCSP project was defined with the aim of reducing the cooling system water consumption and auxiliary power consumption of concentrating solar power (CSP) plants. A full-scale, 24 ft (7.315 m) diameter model of the M-fan was subsequently installed in the Min WaterCSP cooling system test facility, located at Stellenbosch University. The test facility was equipped with an in-line torque arm and speed transducer to measure the power transferred to the fan rotor, as well as a set of rotating vane anemometers upstream of the fan rotor to measure the air volume flow rate passing through the fan. The measured results were compared to those obtained on the 1.542 m diameter ISO 5801 test facility using the fan scaling laws. The comparison showed that the fan power values correlated within +/− 7% to those of the small-scale fan, but at a 1° higher blade setting angle for the full-scale fan. To correlate the expected fan static pressure rise, a CFD analysis of the 24 ft (7.315 m) diameter fan installation was performed. The predicted fan static pressure rise values from the CFD analysis were compared to those measured on the 1.542 m ISO test facility, for the same fan. The simulation made use of an actuator disc model to represent the effect of the fan. The results showed that the predicted results for fan static pressure rise of the installed 24 ft (7.315 m) diameter fan correlated closely (smaller than 1% difference) to those of the 1.542 m diameter fan at its design flowrate but, once again, at approximately 1° higher blade setting angle.

Drilling Riser VIV Tests With Prototype Reynolds Numbers

2013 ◽  
Author(s):  
Halvor Lie ◽  
Henning Braaten ◽  
Jamison Szwalek ◽  
Massimiliano Russo ◽  
Rolf Baarholm
Keyword(s):  
Cross Flow ◽  
Effect Study ◽  
Full Scale ◽  
Scale Model ◽  
Small Scale ◽  
Scaling Effects ◽  
Research Activity ◽  
Forced Motion ◽  
Auxiliary Lines ◽  
Viv Suppression

For deep-water riser systems, Vortex Induced Vibrations (VIV) may cause significant fatigue damage. It appears that the knowledge gap of this phenomenon is considerable and this has caused a high level of research activity over the last decades. Small scale model tests are often used to investigate VIV behaviour. However, one substantial uncertainty in applying such results is scaling effects, i.e. differences in VIV response in full scale flow and small scale flow. To (partly) overcome this obstacle, a new innovative VIV test rig was designed and built at MARINTEK to test a rigid full scale riser model. The rigid riser model is mounted vertically and can either be elastically mounted or be given a forced motion. In the present version, the cylinder can only move in the cross-flow (CF) direction and is restricted in the in-line (IL) direction. The paper reports results from a drilling riser VIV experiment where the new rest rig has been used. The overall objective of the work is to study possible VIV suppression to improve operability of retrievable riser systems with auxiliary lines by adding riser fins. These fins are normally used as devices for protection of the auxiliary lines. The test program has recently been completed and analysis is an on-going activity. However, some results can be reported at this stage and more results are planned to be published. A bare riser model was used in a Reynolds number (Rn) scaling effect study. The riser model was elastically mounted and towed over a reduced velocity range around 4 – 10 in two different Rn ranges, 75 000 – 192 000 (subcritical regime) and 347 000 – 553 000 (critical regime). The difference in the displacement amplitude to diameter ratio, A/D, is found to be significant. The elastically mounted riser was also towed with various drilling riser configurations in order to study VIV/galloping responses. One configuration included a slick joint riser model with 6 kill & choke lines; another has added riser fins too. The riser model is based on a specific drilling riser and the kill and choke lines have various diameters and have a non-symmetrical layout. The various riser configurations have also been used in forced motion tests where the towed model has been given a sinusoidal CF motion. Forces have been measured. Determination of the force coefficients is still in progress and is planned to be reported later. Scaling effects appear to be a significant uncertainty and further research on the subject is recommended. The slick joint drilling riser configuration generally increased the displacements compared to displacements of the bare riser model. The drilling riser configuration with protection fins, kill and choke lines generally reduced the displacements compared to displacements of the bare riser model. For both riser systems, tests showed that the response is sensitive to the heading of the current.

Sign in / Sign up

Export Citation Format

Share Document